[The microbiome in diseases of the nose and paranasal sinuses]

The nasal microbiome refers to the composition and diversity of bacterial communities residing in the nasal cavity. While the gut microbiome has been the primary focus of microbiome research in recent years, driven by advances in diagnostic technologies, increasing attention is now being directed toward microbial ecosystems in other regions of the body, including the respiratory tract. In general, a high and stable microbial diversity (α-diversity) is considered indicative of a "healthy" microbial community. Conversely, reduced bacterial diversity has been associated with clinical conditions, such as chronic rhinosinusitis (CRS); however, it remains unclear whether such microbial alterations are a cause or consequence of the disease, as current evidence does not yet allow for definitive conclusions. Interpreting existing studies on the nasal microbiome is challenging due to several factors: the low microbial biomass in the nasal cavity, the technical difficulty of accurately analyzing such samples, and the lack of standardized methodologies for sampling and data interpretation. These limitations contribute to the heterogeneity of current findings and highlight the need for consistent, guideline-based research protocols in this emerging field.